PITTSBURGH — A football team with two No. 1 quarterbacks in reality has none. A hockey team with two No. 1 goaltenders has a controversy. But a playoff team with four lines and three pairs more likely than not is going to win the Stanley Cup.

And as the Rangers go for a second-round 2-0 lead over the Penguins on Sunday night, they have become the poster team for egalitarianism in the NHL.

The grind of the grueling playoff tournament is ultimately too difficult for teams whose coaches routinely shorten their benches because of either an unyielding philosophy or lack of depth, or a combination of both.

The Rangers who played for John Tortorella know this first-hand after the club’s former coach all but automatically cut down to nine forwards and four defensemen during the 2012, 20-game run that ended two victories shy of the Cup final.

Indeed, the Blueshirts had four defensemen who averaged more than 21:30 of ice per game and two forwards who played more than 22:00 a night while two forwards got an average of 7:04 or less and the sixth defenseman played 6:09 per.

Alain Vigneault knows this from personal experience as well, the Rangers coach having experienced the agony of seven-game defeat to the Bruins in the 2011 final when he was behind the bench of a Vancouver team that lacked the depth to compete with Boston once Roberto Luongo went up in flames.

The Canucks played 25 games that postseason, beginning with a seven-game victory over defending champion Chicago and ending with four defensemen averaging 22:20 or more and four forwards playing more than 20:00 per while a fourth line was used minimally and to negligible effect.

“I think if you look at the teams that have had success and have won the Cup since the [2004-05] lockout, you see those teams have had depth and have been able to play their depth,” Vigneault said Saturday.

“From personal experience, I know when we [the Canucks] lost the Cup to Boston, Boston was a four-line team — probably the best fourth line, I felt, in the league,” the coach said, referring to the unit that generally featured Gregory Campbell, Daniel Paille and Shawn Thornton. “We didn’t have four lines.

“From that experience, if you can play four lines and manage the minutes, I think you can play at a higher tempo and faster paced game.”

In essence, that defines the overriding philosophy Vigneault has brought to the Rangers, who don’t have single forward averaging 20:00 a game nor a defenseman averaging 25:00 a night — and conversely, don’t have a forward getting less than 9:30 per (9:32 for Derek Dorsett, who doesn’t get time on the specialty units) or a defenseman under 13:25.

“Even at this point of the playoffs, with the schedule we have, being able to roll four lines and three pairs on D makes a huge difference,” said Marc Staal, whose club will play its fourth match in six nights on Sunday before playing at the Garden on Monday and Wednesday to hit six games in nine nights. “It gives you time to recover on the bench, which is so important.

“It’s a little different look from us, isn’t it?”

It’s also different for upper-echelon players accustomed to piling up minutes. There’s a different rhythm to going on every fourth turn and extending the length of shifts. No one overstays his shift playing for Vigneault, whose high-pitched command of “Chaaaaange” from behind the bench is both as piercing and effective as a dog whistle. It is not, however, as if the Rangers weren’t warned.

“He brought it up real early, right at the start of training camp and then the message was sent again during the season when we slipped into taking longer shifts,” said Brad Richards, averaging 17:10, two years after getting 22:11 a night. “Everybody wants to be out there, but if everybody buys in, then you’re right back on.

“Our second half of the season, we had our success with four lines and everyone bought in. It’s common sense in the new NHL, where there are better players, young guys with energy, the cap system.
“Teams that roll four lines and stay with short shifts are able to stay fresh deep into the playoffs.”

And a coach and a team, who learned separately the hard way, are committed to doing just that.